AddFlag helper method for expressions

Disco.Services/Expressions/Extensions/UserExt.cs

@@ -1,6 +1,8 @@
-using Disco.Models.Repository;
+using Disco.Data.Repository;
+using Disco.Models.Repository;
 using Disco.Services.Users;
 using System;
+using System.Data.Entity;
 using System.Linq;
 
 namespace Disco.Services.Expressions.Extensions
@@ -69,5 +71,41 @@ namespace Disco.Services.Expressions.Extensions
             return authorization.HasAny(Claims);
         }
         #endregion
+
+        #region Flag Extensions
+
+        public static bool AddFlag(User user, string flagName, User techUser)
+            => AddFlag(user, flagName, techUser, comments: null);
+
+        public static bool AddFlag(User user, string flagName, User techUser, string comments)
+        {
+            using (var database = new DiscoDataContext())
+            {
+                database.Configuration.LazyLoadingEnabled = true;
+
+                var flag = database.UserFlags.Single(f => f.Name == flagName);
+                if (flag == null)
+                    throw new ArgumentException("Invalid User Flag Name", nameof(flagName));
+
+                var flagUser = database.Users.Include(u => u.UserFlagAssignments).FirstOrDefault(u => u.UserId == user.UserId);
+                if (flagUser == null)
+                    throw new ArgumentException("Invalid User", nameof(user));
+
+                if (flagUser.UserFlagAssignments.Any(fa => !fa.RemovedDate.HasValue && fa.UserFlagId == flag.Id))
+                    return false;
+
+                var addingUser = database.Users.Find(techUser.UserId);
+                if (addingUser == null)
+                    throw new ArgumentException("Invalid Tech User", nameof(techUser));
+
+                var userFlagAssignment = flagUser.OnAddUserFlagUnsafe(database, flag, addingUser, comments);
+
+                database.SaveChanges();
+            }
+
+            return true;
+        }
+
+        #endregion
     }
 }